Production of disk sound-records.



No. 878,547. PATENTBD PEB.11, 1908 T. H. MACDONALD. PRODUGTIUN OF DISKSOUND RECORDS.

APPLIGATION FILED SEPT. 8, 1906.

BODY OF EARTHY 05? h uwrmnngjmm I TPAPER msc com'mn I "WITH SHELL/MCOMPOSITION 3 rum u ['01 Climate m invented a new and useful Productionof THOMAS H. MACDONALD, BRIGE'TEPORI, CONNECTICUT, .l-iSSli lNtl lt TOAMERICAN GRAYHOPHONE C-f lfdidll l', OF BR IDGEPOIL'T, (JUNNEU'IIUUT, ACORPORATION OF WEST VIRGINIA.

PRGDUCTZON OF DISK SO'QND-BECORD".

Specification of Letters Patent.

Patented Feb. 11, 1908.

App ication filed September 8.1906. Serial No. 333,812.

T 0 all whom it may concern:

Be it known that I, 'iuotrss H. MAonoN- ALD, a citizen of the UnitedStates, and a resident of Bridgeport, Connecticut, have Disk SoundRecords, which improvement is full set forth in the followingspecification.

' The present invcntionrela more particularly to the manufacture of dishs nnul-records, and has for its object to i-heapcn the production ofsuch records, and at the same time to improve their quality, especiallyin re spect to strength, durability, and uniformity of product.

Sound-records of the disk type are, and for many years have been, madeof compositions of heavy earthy material compacted by means of shellac.Various earthy mate- I rials have been used, in varying pro ortions,each manufacturer having his own formula, but shellac is an essentialingredient of all, and is that which contributes chiefly to the .cost ofthe composition. Generally, the shellac is distributed. uniformlytlusmighout the mass, :its primary purpose heinp -s a binding material.It has, however, been discovered that the essential advantage of thepresence of shellac in hese cmnpositions when used for sound-recm'ds, isthe gluzed surface imparted by that material, and for which nosubstitute has as yet oecn found. The effect of the peculiar surface dueto the resence of shellac is to cause the reproduclng stylus to slideeasily and smoothly along the record r'oove, thus produciin, good toneuality and also prolonging the-life time of t e record. Without shellacin proper pro portion in the surface, the reproduction would beextremely harsh, and the record would be destroyed after a very fewrepro ductions. 'As the result of this discovery of the special functionof the shellac it has been found that sound1'cco1'i,ls of the bestquality can be produced by confining shellac sub stantially to thesurface of the record tablet, and em loying armther material a binder inthe ody of the tablet. .he improvement just referred to is desc ibed inthe lioyt and Gaven Patents Nos. 30-,5-12, 80$,l.-'l3, and 809,263, alldated January 2, 1906. The result is a tablet of practically homogeneouscomposition quite indistinguishable in aparance from, and exhibiting thesame lacture as, sound records wherein shellac is used uniformlythroughout the tablet. E-y

this Hoyt and (laven processa very large economy is effected in themanufacture of the souml-1'ecords.

In carrying out the Hoyt and Gaven process care must be taken to form acontinuous layer of the smfacing material over the inforior bodymaterial. Should the latter come to the surface, even for a very smallarea, a soft s mt would result, and the sound-record woulu be defective.As a precaution against such possibility, and against lack of care onthe part of the iwn'hnian, the surface layer is made of greaterthickness than is necessary relative to ,the depth of the record-groove.

in carrying out the present invention, paper (preferably hard paper) iscut into disks of proper size, and i. may then proceed either to coatthe paper with shellac solution and dust with shellac powder, or I maytake the dry paper and dust it with the dry snellac powder and thenapply heat. The shellac powder employed may he more or less pureshellac, or may consist. of shellac and other ingredients and anydesired coloring matter, and the term shellac powder as hereinafteremployed is intended to include both the pure shellac and shellac withother ingredients. in either case the result is an article thatson'ipwhat resembles ordinary sand-paper in appearance, the particles orgranules of the shellac powder adhering firmly and closely to thesurface of the paper. 'lhese coated paper disks may be prepared inquantities and delivered to the workmen when needed for making records.To complete the record, the shellac-dusted paper disk is placed facedownward upon the heated matrix, a sullicicnt amount of plasticbacking-material is placed on the back of the paper, and the whole ispressed in the usual manner. The finished record shows no sign of thepaper, which is concealed by the surfacing of the shellac powder. Thisshellac powder may he made of more or less pure shellac, or may containother ingredients such as celluloid, etc, and any desired coloringmatter. lfhirthormorc, i: may apply a disk of paper at the hack of thebackingnuiterial, so that the finished article will have one or two (ifthe second sheet of paper be employed) sheets as a binder, which servesto reinforce and stiller. the record.

Instead of applying the backing to the shellac-dusted paper While thelatter is upon the matrix and compressing the whole to as great economy;The amount of powder necessary to coat the paper is only from onehalf tothree-quarters of an ounce, whereas the smallest amount that can beemployed under the present process is about two ounces;

moreover, in making such records in a factory employing hundreds ofpressmen, there is inevitably considerable waste, owing to carelessness,but in carrying out my present invention the preparation of theshellacdusted paper would be in a special room and by men trained to dojust that work and nothing else. This shows a saving of at leastseventy-five per cent. of shellac-powder which is an element of greatexpense in the making of sound-records. The second advantage is thatrecords can be made more rapidly in this manner than in the old way. Athird advantage is, as already indicated, that the sheet of paper seemsto stiffen the record and renders it more durable.

In the accompanying drawing is shown part of a press for pressingdisksoundrecords, and also a disk of paper coated with the record-surfacematerial, and a backing of earthy (or other suitable plastic) material,therein, illustrating the method by which disk sound-records areproduced according to the present invention.

The product of the above-described process is not claimed herein, beinmade the subject-matter of a separate app ioation.

Having thus described my invention, I claim:

1. The process which consists in coating sheets of paper with plasticmaterial, and

uniting two or more coated. sheets to form a Henna-r1 talxlnf.

erase? 2; The process of manufacturing disk sound-records, whichconsists of applying shellac-powder to a disk of paper, applying thesame upon a recordanatriir, applying suitable backing-material upon theback of the paper, and compressing the same.

3. The process of manufacturing disk sound-records, which consistsofapplying shellac-powder to a disk of paper, applying the same upon arecord-matrix, applying suitable backing-material upon the hack of thepaper, and compressing the same under heat.

4. The process of manufacturing disk sound-records, which consists ofapplying a shellac solution to a disk of paper, dusting the same withshellac powder, drying it, and compressing the same with a suite hiebacking against a record-matrix.

5. The process of manufacturing disk sound-records, which consists ofapplying a shellac solution to a disk of paper, dusting the samewithshellac powder, dryin it, and compressing the same with a suitablebacking against a record-matriX in the presence of heat.

6. The process of manufacturing a disk sound-record, which consists ofapplying shellac powder to a paper disk, heating the same causing it toadhere, and subsequently compressing the same with a suitable backingagainst a record-matrix. I

7. The process of manufacturing disk sound-records, which consists ofpreparing a shellac dusted paper, applying the same to a suitablebacking, and compressing the whole against a record-matrix.

8. The process of manufacturing disk sound-records, which consists ofpreparing a shellac-dusted paper, applying the same to a suitablebacking, and compressing the whole ag inst a record-matrix under heat.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

THUMAS H. MACDONALD.

Witnesses:

A. B. Kno'een, R. T. PITT

